Ship having a deck comprising a cavity with a built-in rotary plate

ABSTRACT

A ship for laying flexible undersea lines at sea, the ship having a deck including a cavity receiving said turntable and a motor-driven device for rotating the turntable and fastened to the carrier structure of the hull of the ship, also known as the “hull girder”. The top face of the circular turntable does not project significantly above the plane of the deck that is juxtaposed therewith. The turntable presents attachment elements for attaching a modular storage and handling device for storing and handling flexible lines by winding and unwinding the flexible lines.

RELATED APPLICATIONS

This is a U.S. national stage of application No. PCT/FR2011/052224, filed on Sep. 26, 2011. Priority is claimed on the following applications: French Application No.: 1058734 filed on Oct. 25, 2010; and French Application No.: 1059509 filed on Nov. 19, 2010, the content of which are incorporated here by reference.

FIELD OF THE INVENTION

The present invention relates to equipment for loading, transporting, and laying flexible lines, such as flexible pipes or control umbilicals including electrical cables and arranged on board floating supports in order to be installed at sea.

BACKGROUND OF THE INVENTION

The technical sector of the invention is more particularly the field of installing lines resting on the sea bottom, and in particular including risers having flexible pipes for extracting oil, gas, or other soluble or fusible material or a suspension of mineral material from under the sea via an underwater well head and up to a floating support, in order to develop production fields installed out at sea, off shore. The main and immediate application of the invention lies in the field of producing oil at sea.

The flexible pipes used as production or service lines for conveying liquid or gaseous hydrocarbons present great mechanical strength, in particular against internal pressure, against traction, and against flattening, and they are usually laid by means of winches or traction devices such as “caterpullers” (i.e. tensioners having crawler tracks fitted with shoes that clamp against the line and that move continuously in translation in order to entrain the line therewith), or indeed by combining both winches and caterpullers.

The traction forces applied by such caterpuller devices on a flexible pipe can be considerable when laying at great depth, and the compression forces exerted by the shoes on the line must be high enough to avoid any relative slip between the shoes and the line.

A control umbilical includes one or more hydraulic lines and/or electric cables for transmitting power and/or information.

The lines referred to as “flexible pipes” are well known in the art and they are described in standards documents published by the American Petroleum Institute (API), and more particularly under the references API 17J and API RP 17 B. Such flexible pipes are manufactured and sold in particular by the supplier Coflexip France.

As a general rule, such flexible pipes comprise inner sealing layers of thermoplastic material associated with layers that withstand the pressure inside the line, generally made of steel or of composite materials. Such flexible pipes are constituted more particularly by assembling layers of tubular thermoplastic materials and strong layers of steel or of composite materials made in the form of spiral-wound strips with touching turns inside the thermoplastic pipe in order to withstand internal bursting pressure, and associated with external reinforcement over the thermoplastic tubular layer and likewise in the form of touching spiral-wound strips, but at a pitch that is longer, i.e. with a smaller helical slope angle, in particular lying in the range 15° to 55°.

In the present description, the term “undersea flexible line” is used more generally to designate a cable, an umbilical, or a pipe capable of accepting a large amount of deformation without giving rise to large return forces, and in particular a flexible pipe.

In the prior art, ships for laying flexible lines at sea are fitted with devices for storing and handling said lines as described below with reference to FIG. 4. Most conventionally, a series of winches or drums of horizontal axis have line portions wound thereon and are arranged adjacent to one another in the longitudinal direction of the ship. The various line portions are thus wound on a plurality of winches, each having a horizontal cylinder between two vertical side plates. In that type of prior art embodiment, the horizontal cylinder needs to present stiffness in bending because the weight of the wound line is taken up entirely by the cylinder.

Furthermore, the weight of the line and of the winch including its vertical side plates is transmitted in full to the motor drive for the drum. This results in the winches necessarily presenting a plate size and a windable capacity in terms of line length that are limited, particularly when the diameter of the line is larger.

With flexible lines of large diameter, such conventional storage on winches as shown in FIG. 4 is often not possible since the minimum radius of curvature of such a flexible line is very large, and in particular may be as much as 5 meters (m) or more, thereby requiring drums to be of very large size and therefore unsuitable for handling.

Thus, in practice, the diameter of the end plates does not exceed 5 m to 10 m for a drum weighing 400 (metric) tonnes (t) to 500 t corresponding to portions of line presenting lengths of less than 10 kilometers (km) and in particular lengths of 1 km to 10 km for line diameters of 50 millimeters (mm) to 300 mm, which is why it is necessary, when laying lines of great length and/or of large diameter, to make use of a large number of winches that are thus arranged adjacent to one another. Finally, connecting together the various line portions in order to constitute a complete line providing a bottom-to-surface connection represents handling operations that are relatively difficult and lengthy to perform and that require the laying ship to be out of operation for long periods of time, thus representing large costs.

Devices are also known for storing and handling flexible lines that involve using “winch” type winder devices having a cylinder on which the line is wound that is vertical, with that type of device either being placed on the deck of the ship or else installed inside the ship, generally at the bottom of a hold. Nevertheless, under such circumstances, the fact that the bottom plate of the winch is arranged horizontally over the deck of the ship means that that plate receives the load in full and needs to be supported by a support and rotation device that must present a very high degree of stiffness so as to be capable, on its own, of withstanding compression forces and also bending and/or twisting forces, since the plate constitutes a turntable that needs to be kept properly plane so that the winch can be rotated about its vertical axis in a manner that is stable and accurate; it is also necessary for said winch to be removable after it has been used in order to release the deck of the ship for other operations.

Installing such equipment is difficult, since it requires the use of powerful hoist means given that the structure carrying the turntable together with said turntable presents a weight in the range 250 t to 750 t, or even more under extreme circumstances. Thus, such equipment can be installed or removed only in a sheltered zone, generally in a port, thereby preventing the ship from being used for a period of four to five days, or even several weeks.

WO 2004/068012 describes devices for storing lines by winding them, such a device comprising a circular turntable mounted over a bottom supporting surface situated above the deck of the ship on which the line storage device is installed.

In WO 2004/068012, the line storage device operates by winding in a mixed carousel and rotary basket mode described in FIG. 4B, in which an umbilical 10422 of small diameter is wound in “basket” mode (in the meaning of the definition given in paragraph (e) below concerning a storage device of the invention), the umbilical being wound against a central cylinder of the storage device, while a line 1044 of larger diameter is wound in “carousel” mode (in the meaning of the definition given in paragraph (b) below in the definition of the modular storage device of the present invention) outside posts or other retaining means of the storage device.

Thus, given the fact that the line 10422 is wound in basket mode, the central cylinder is not covered by an end plate of diameter greater than the diameter of the cylinder. On the contrary, the top opening between the central cylinder and the peripheral means 10406 for retaining the line 10422 is empty.

In contrast, a top plate 10408 is added to the tops of the winding support elements 10406 outside which and against which the line 1044 is wound in carousel mode.

In document WO 2004/068012, of necessity, the umbilical or the line wound in basket mode around the central cylinder must accommodate a smaller minimum radius of curvature and must therefore present a smaller diameter.

The embodiment of the mixed storage device described in WO 2004/068012 presents the drawback of requiring a central cylinder of larger diameter when the lines stored in basket mode are of large diameter, thereby making the storage zone situated between said cylinder and the axis of the basket unusable, so the overall storage capacity is thus severely reduced compared with the storage mode of the present invention. In addition, it is more difficult to perform winding in basket mode with lines or umbilicals of small diameter since winding is not performed under tension and requires more accurate control that is therefore more difficult to perform in order to form concentric turns all lying on a common plane, particularly since the diameter of the line and the diameters of the turns are small.

EP 1 118 572 confirms the analysis given above about the difficulty of winding a multi-turn layer in basket mode, the layer comprising a plurality of concentric turns resting on a common plane and being constituted by a line of small diameter, as is required in basket mode.

In WO 2004/068012, EP 1 118 572, and WO 2009/129223 which describe devices for storing lines by winding on board a ship for laying the lines at sea and including a turntable or a bottom plate, said turntable or bottom plate of the device is situated over the deck of the ship.

SUMMARY OF THE INVENTION

The object of the present invention is to provide an improved novel device for storing and holding flexible line on the deck of a ship for transporting such lines and for laying them at sea.

More particularly, the object of the invention is to provide a device for storing and handling flexible lines on board laying ships that makes it possible to perform operations of laying said flexible lines at sea that are longer, that can be laid more easily, and that can be laid more quickly; still more particularly, the object of the invention is to make it possible to release the deck of the ship more easily and more quickly once the line-laying operations have been completed and to reinstall the device as required for a new line-laying operation, as easily and as quickly as possible and to do so with relatively small handling means, thus making it possible, where necessary, for handling to be performed on site.

To do this, the present invention provides a laying ship for laying flexible undersea lines at sea, the ship having a deck including a cavity having arranged therein said circular turntable and a motor-driven support and rotation device for the turntable, the top face of said turntable not projecting significantly beyond the level of the portion of the deck that is immediately juxtaposed (or adjacent) laterally thereto, the periphery of said turntable preferably coming level with said deck, said turntable being supported by and co-operating in rotation with elements of the support and rotation device fastened to the carrier structure of the hull of the ship within said cavity, said rotary turntable presenting attachment elements on its top face and suitable for releasably attaching accessories to a modular device for storing and handling by winding and unwinding said flexible line(s), said accessories including at least winding supports extending in a direction ZZ′ perpendicular to and above said plane of the deck of the ship, and preferably disposed circularly and symmetrically relative to the central axis of ration Z₁Z₁′ of said turntable, said attachment elements for said winding support elements preferably being distributed regularly on the top face of said turntable, and also preferably distributed circularly and symmetrically at different distances from the vertical central axis of rotation Z₁Z₁′ of said turntable.

It can be understood that each portion of the top face of said turntable does not project significantly from the level of the portion of the plane of the deck that is adjacent thereto, i.e. the closest portion, in a direction that is perpendicular to said plane at said plane portion.

The term “carrier structure of the hull of the ship” is used herein to mean the structure that is also commonly referred to as the “hull girder”, which structure serves to support the ship proper together with its load, both on the deck and in its hold, when the hull is subjected to buoyancy thrust. In the manner known to the person skilled in the art, the hull girder has main transverse structural elements known as “frames” and secondary transverse and longitudinal structural elements known as “bulb profiles” together with longitudinal structural elements in the form of “primary beams”, with the top portions of said structural elements supporting the deck of the ship.

The term “deck of the ship” is used herein to mean the top wall of the hull girder, which top wall is made of thick sheet metal known as the “deck plate”. It is generally continuous from the stern of the ship to the bow of the ship and towards the sides, from port to starboard. This top wall is substantially horizontal or possibly slopes a little from and on either side of the middle longitudinal axis of the deck towards the respective sides of the ship. A running portion of the deck is thus constituted by thick sheet metal plates secured to said transverse structural elements of the frame or bulb profile type and to said longitudinal structural elements situated under said deck plate.

It can be understood that in the present invention, the ship has a hull girder that is configured during building of the ship so as to create a said cavity that is suitable for receiving and supporting said turntable and its support and rotary drive device together with the load on said turntable, in particular said device for storing and handling flexible lines and the line(s) stored on said turntable.

A first advantage of the invention stems from the principle of having a turntable incorporated in a cavity in the deck, thus avoiding any need to remove the turntable, so the turntable can be left in place permanently. This represents a considerable saving of time. Since said turntable does not project significantly above the plane of the deck, and also since it includes releasable attachment means for a said modular storage and handling device, it is possible to install and remove said modular device of the invention much more easily and much more quickly than prior art devices for storing and handling flexible lines, and to do so with very limited hoisting and handling means, thus making it possible under certain circumstances to perform this type of operation directly on site without any need to return to port.

Thus, by means of the device of the invention, the major portion of the weight of the equipment, i.e. the turntable and its motor drive, stays permanently in place since they are permanently incorporated in the cavity in the deck of the ship and they require large weights to be handled only while said ship is being built or while said turntable and its support and rotary drive device are being incorporated in the cavity in the deck of the ship. Likewise, the rigid structure for supporting the turntable that exists in the prior art is replaced by the load-carrying structure of the ship itself, possibly with local reinforcement, and thus remains permanently incorporated in the ship together with the device of the invention, and therefore does not require large weight to be handled except when building said ship or when incorporating said turntable and the support and rotary drive device within the cavity in the deck of the ship, said turntable and the rigid support structure as they exist in the prior art possibly representing a total weight of 150 t to 750 t, or even more.

Also as a result of this permanent incorporation of the turntable and its rotary drive device within said cavity, the stiffness required of said turntable is relatively small, since said turntable is only required to transfer the forces that result from the load it is carrying, without any need also to transfer possible repeated twisting and/or bending forces as would be necessary if said turntable needed to be capable of being handled and moved together with its support and rotary drive device after each occasion it is used, as in the prior art.

More particularly, the carrier structure of said turntable comprises a floor incorporated in the hull girder and forming an integral portion of said hull girder, constituting a downward setback of a substantially circular portion of the deck, said floor constituting the top wall of the hull girder within said cavity and performing a role that is similar to that of the deck plate in terms of the strength of said hull girder.

Preferably, said floor is secured to additional reinforcing elements within the cavity and that form integral portions of the hull girder that is configured in such a manner that the hull girder is capable of transferring the load constituted by said turntable, said support and rotary drive device, and its load, and is capable of providing the stiffness required for supporting said turntable and its load.

In a particular embodiment, said carrier structure of the hull includes additional reinforcing elements in said cavity, and said support and rotation device within said cavity comprises at least:

-   -   a floor fastened to and supported by said additional reinforcing         elements of said carrier structure of the hull under said floor;     -   rotary guide elements preferably comprising wheels supported by         said floor and a rotary shaft supported by additional         reinforcing elements of said carrier structure of the hull under         said floor; and     -   a motor and rotary drive elements for driving the turntable         and/or said rotary shaft in rotation by actuating said motor,         the elements being supported by structural elements of said         carrier structure of the hull at the periphery of said cavity         and/or of said additional reinforcing elements of said carrier         structure of the hull in said cavity, said rotary drive elements         preferably comprising gearing. Said rotary drive elements may         also comprise wheels or belts.

The term “additional reinforcing elements” is used to mean structural elements that are additional compared with the remainder of the load-carrying structure of the hull, and suitable for ensuring that the load-carrying structure of the hull in the cavity has the ability to take up the compression loads represented by the turntable and its loading as transferred locally directly to the load-carrying structure of the hull of the ship in the cavity as a result of the support and rotary drive elements of the turntable being fastened directly to the load-carrying structure of the hull. It is thus possible to make use of modular storage and handling devices of the invention that are of large capacity and thus possibly to use lines that are of great length and/or of large diameter compared with modular devices supported by turntables that are fitted over the deck of a ship in which the hull girder is not specially configured with a cavity and additional reinforcing structures within the hull girder for supporting the turntable, and without requiring the support structure for the turntable to be put into place on the deck in order to take up a fraction of the compression loads and in order to provide said turntable with stiffness, as applies in the prior art.

More particularly, said additional reinforcing elements of said load-carrying structure of the hull supporting said floor within said cavity comprise transverse frames that are lower but closer together in the longitudinal direction of the ship and longitudinal beams that are lower but closer to one another in the transverse direction of the ship.

The term “releasable attachment” is used to mean that said accessories can be installed and then removed in order to make room above said turntable.

It can be understood that said accessories are suitable for co-operating with said turntable to form a modular device for storing and handling flexible line(s) by winding and unwinding said flexible line(s).

It can be understood that because said attachment elements can be positioned at different distances from the vertical central axis of rotation Z₁Z₁′ of said turntable, it is possible to attach said winding supports thereon at various positions, thereby enabling a variety of diameters to be wound, depending on the positions of said winding supports on the surface of the turntable.

More particularly, said attachment elements comprise grooves and/or preferably threaded holes arranged radially and/or circularly, and preferably regularly distributed over the entire surface of the turntable.

It is thus easy with very limited handling means to position said accessories so as to form winding supports that enable windings of various diameters to be wound on the surface of the turntable. Said grooves are a known way of providing releasable fastening co-operation with elements that co-operate with or that are incorporated in the structural portions at the bottoms of said accessories and that are suitable for sliding therein, such as cleats. Said holes are suitable for co-operating to provide releasable fastening with rods that are fastened in or incorporated in the bases of said accessories.

The present invention thus provides a laying ship supporting a modular device for storing and handling flexible line by winding and unwinding flexible line, the ship comprising:

a) a said turntable supporting said accessories on its top face, which accessories are reversibly attached to said attachment elements, said accessories thus forming one or more winding supports extending in the perpendicular direction ZZ′ and above said plane of said deck of the ship, said winding supports being arranged circularly and symmetrically relative to the central axis of rotation Z₁Z₁′ of said turntable on the top face of said turntable; and

b) a spooler device comprising a flexible line guide and holder device mounted on a second support element forming a post, a tower, or a gantry extending at least in a direction perpendicular to and above the deck of the ship in the proximity of said turntable and including motor-driven means for moving a first flexible line portion extending between said guide and holding device and said storage and handling device, and suitable for enabling vertical and/or horizontal movement of said flexible line portion relative to said second support element in order to enable said flexible line to be spooled around and against said winding supports.

It can be understood that said deck includes, close to said turntable, at least one second attachment element for attaching at least one said second support element.

In conventional manner, the term “spooling” is used herein to mean the action of guiding said line that is being arranged in touching turns for winding and unwinding purposes:

-   -   either by moving said line vertically synchronously with the         rotation of said turntable, said turns then being juxtaposed one         above another in superposed manner;     -   or else by moving said line horizontally synchronously with the         rotation of said turntable, said turns resting on a common plane         and having winding diameters that vary continuously since they         are spiral-wound, being juxtaposed concentrically one beside         another.

In a first variant embodiment, the device for storing and handling flexible line is of the type known as the “carousel” type and comprises:

a) a winding support having a continuous wall in the form of a tapering or right central cylinder arranged coaxially about the axis of said turntable, said cylinder being surmounted by a top circular plate at its top and preferably having the same diameter as said turntable; and

b) a spooler device suitable for spooling said flexible line around and against said central cylinder in said “carousel” mode, comprising a line traction device suitable for tensioning said first line portion extending between said traction device and the already-wound or still-wound portion of line, said traction device preferably being a caterpuller, and means suitable for moving said tensioned first flexible line portion vertically in such a manner as to keep it substantially horizontal while it is being wound or unwound so as to enable the line to be spooled in a plurality of coaxial layers of touching turns and enabling it to be unwound, said flexible line thus being wound or being suitable for being wound in “carousel” mode in a plurality of layers such that the turns of any one layer are helically superposed, the various layers forming juxtaposed coaxial cylindrical columns, preferably by moving the traction device vertically.

It can be understood that:

-   -   the turns of the first layer are applied against said cylinder         and present a smallest winding diameter, and the turns of the         second layer that are applied against the turns of the first         layer present a greater winding diameter, with the following         cylindrical layers being applied in succession against the         preceding layers and each presenting a greater winding diameter,         such that two turns of two juxtaposed layers present winding         diameters that are different; and     -   the first layer is preferably formed by spooling the line         upwards so as to superpose the turns successively one above         another from said turntable on which the first turn rests at the         bottom up to a top plate against which the top face of the last         turn on top comes to abut, while the second layer is made by         spooling downwards from the underface of the top plate until the         turntable is reached. This explains why it is necessary to         maintain tension in the line portion between the holder and         guide device and the already-wound or still-wound line portion         on the winding support, since otherwise not only would it be         impossible for the line to remain wound in stable manner, but it         would also be impossible to perform winding while spooling         downwards.

In this carousel mode of winding, a winding support is used that preferably has a wall that is continuous and in the form of a tapering or right central cylinder since the line needs to be spooled under tension and, if a plurality of post type winding supports distributed regularly around the circle were in use, it would run the risk of suffering excessive bending and in particular bending with a radius of curvature smaller than its minimum radius of curvature at its points of contact with said posts, thus running the risk of damaging the inner structure of said flexible lines.

More particularly, for this carousel mode winding, the line may be wound in k=2 to 100 coaxial layers, each layer comprising l=2 to 100 turns, and preferably five to ten turns that are helically superposed.

In a second variant embodiment, the flexible line storage and handling device is of the type known as the “rotary basket” type and comprises:

a) a plurality of winding supports in the form of inner posts arranged circularly and preferably symmetrically relative to the axis of rotation Z₁Z₁′ of said turntable or a tapering or right central cylinder arranged on the axis with said turntable, and peripheral retaining elements extending in the perpendicular direction ZZ′ above said deck of the ship, being disposed circularly and preferably symmetrically relative to the central axis of rotation Z₁Z₁′ of said turntable on the top face of said turntable, and also preferably regularly distributed at the periphery of said turntable;

b) a spooler device suitable for spooling said flexible line around and against said central cylinder or said plurality of inner posts in “rotary basket” mode comprising a line holder and guide device, preferably a caterpuller, and means suitable for moving the first flexible line portion in horizontal translation in a transverse direction YY′ perpendicular to said vertical central axis of rotation Z₁Z₁′, the first flexible line portion extending in an inclined and in particular curved position between said holder and guide device and the already-wound or still-wound line, preferably by moving said traction device horizontally so as to enable the line to be spooled as a plurality of superposed layers of touching turns and so as to enable it to be unwound, the flexible line thus being wound or being suitable for being wound in “rotary basket” type mode as a plurality of superposed layers such that the turns in any one layer are juxtaposed concentrically, lying on a common plane and presenting diameters that increase from the first turn pressed against the winding support(s) out to the last turn coming into abutment against said peripheral posts, said line portion extending between the holder and guide device and the already-wound or still-wound line without being tensioned by said holder and guide device, which is held at constant height above the top ends of said winding supports and said retaining posts.

It can be understood that:

-   -   the first layer is formed by placing it on the turntable and         moving said line portion progressively away from the central         cylinder (or the inner winding support posts) starting from a         first turn that is juxtaposed with said central cylinder and         going out to a last turn at the periphery of the turntable (“go         direction”); and then     -   the second layer is formed by laying the second layer on top of         the first layer, while moving said line portion in the opposite         direction (“return direction”), i.e. moving the line closer to         the central cylinder; and     -   so on in the go and return directions for moving the         not-yet-wound line portion for the following layers (or inner         winding support posts) from the first peripheral turn superposed         on the last turn of the preceding layer where it is stabilized         and held by said peripheral retaining posts going towards said         central cylinder, and so on in the opposite travel direction for         the not-yet-wound line portion for the following layer; said         movements of said line portion in the go direction (away from)         and then in the return direction (towards) the central cylinder         for spooling purposes being synchronized with the rotation of         the turntable.

Preferably, in the “rotary basket” type embodiment, said inner posts forming said winding support elements and also said peripheral retaining posts are connected together in particular by respective circular rails at their tops. Furthermore, in this “rotary basket” type embodiment, the space between said retaining elements and the central cylinder or said winding support elements does not include a top plate that would obstruct the passage and prevent proper winding/unwinding of said non-tensioned first line portion against said support elements, insofar as said first line portion is not arranged horizontally, but is inclined from the holder and guide device towards said winding support elements situated below said central cylinder, and insofar as said first line portion must be capable of being moved in horizontal translation in said space.

In the present description, the term “circularly arranged” is used to mean that said elements are arranged along a circle, and in particular when referring to posts, that the bases and the tops of said posts are arranged along respective circles.

More particularly, in basket mode, a line is wound over m=2 to 100 superposed layers, each layer having p=1 to 50 turns, and preferably 5 to 20 coaxial touching turns.

In a preferred third variant embodiment of the invention, the flexible line storage and handling device is of the mixed carousel and rotary basket type and is suitable for storing and handling two flexible lines, the device comprising:

-   -   a first winding support for a first line, said first winding         support having a continuous wall in the form of a tapering or         right central cylinder arranged coaxially about the axis of said         turntable;     -   a plurality of second winding supports for winding a second         line, the supports being in the form of inner posts arranged         circularly and preferably symmetrically relative to the central         axis of rotation Z₁Z₁′ of said turntable at a constant radial         distance from said central cylinder, and also preferably         distributed regularly along their said circular line of         positioning on said turntable;     -   peripheral retaining elements in the form of posts extending in         the perpendicular direction ZZ′ above said plane of said ship         deck, arranged circularly and preferably symmetrically relative         to the central axis of rotation Z₁Z₁′ of said turntable and also         preferably distributed regularly at the periphery of said         turntable;     -   said central cylinder being surmounted by a top circular plate         at its top and of diameter such that said inner winding posts of         the second line are secured to one another at their tops by         being fastened to the periphery of said top plate, said first         and second support elements and said retaining elements being         arranged on the top face of said turntable;     -   a spooler device including at least a second support element for         supporting at least one flexible line guide and holder device         suitable for enabling a said first flexible line portion to be         moved vertically and/or horizontally, the first flexible line         portion extending between the guide and holder device and the         already-wound or still-wound line for spooling said flexible         line around and against said winding supports, said second         support element forming a tower or a gantry extending at least         in a direction ZZ′ perpendicular to the plane of said and above         said bridge, in the proximity of said turntable;     -   a said flexible guide and holder device being suitable for         enabling a first flexible line to be spooled around and against         said central cylinder in “carousel” mode and comprising a line         traction device suitable for tensioning the first line portion         extending between the traction device and the already-wound or         still-wound first line, said traction device preferably being a         caterpuller, and means suitable for vertically moving said first         flexible line portion extending between the traction device and         the already-wound or still-wound first line so that it can be         tensioned and held substantially horizontally by said traction         device to enable the first line to be spooled as a plurality of         coaxial layers of superposed touching turns, said first flexible         line thus being wound or being suitable for being wound as a         plurality of coaxial layers such that the turns in any one layer         are superposed helically, the various layers forming juxtaposed         coaxial cylindrical columns such that two turns of two         juxtaposed layers present different diameters; and     -   a said flexible line guide and holder device also being suitable         for enabling a second flexible line to be spooled around and         against said winding supports in the form of inner posts in         “rotary basket” type mode, comprising a device for holding and         guiding the line, preferably a caterpuller, and means suitable         for moving said portion of the second flexible line in         horizontal translation in a transverse direction YY′         perpendicular to said central axis of rotation Z₁Z₁′, said first         portion of the second flexible line extending in an inclined and         in particular curved position between the holder and guide         device and the already-wound or still-wound second line in order         to enable said second line to be spooled as a plurality of         superposed layers of touching turns, said second flexible line         thus being wound or being suitable for being wound as a         plurality of superposed layers such that the turns in any one         layer are concentrically juxtaposed, resting on a common plane         and having diameters that increase from the first turn pressed         against said winding supports in the form of inner posts to the         last turn coming into abutment against said peripheral retaining         posts, said first portion of the second line not being tensioned         by said holder and guide device, which is held at a constant         height above said winding supports and said retaining posts.

It can be understood that said first portion of the second line is thus inclined and curved between said holder and guide device and the already-wound or still-wound second line, and that it passes through the empty space between said retaining elements and said support elements, said space not being obstructed by a top plate.

For the rotary basket winding of the second line, the use of a plurality of posts as winding supports presents less risk of the second line being subjected to excessive curvature since the flexible line is not under tension.

More particularly, in this third variant embodiment, the storage and handling device comprises a single line guide and holder device suitable for being moved vertically or horizontally at constant height to move relative to a second support element of said flexible line guide and holder device, said second support element comprising a gantry.

This embodiment is the preferred embodiment of the flexible line storage and handling device since it makes it possible to avoid using two distinct pieces of equipment or a single piece of equipment that requires major transformations that are difficult to perform on site, on the open sea, in order to change between carousel mode winding and rotary basket mode winding, thereby avoiding the ship being expensively held up in port.

The embodiment referred to as being of the “mixed” type is also preferred since it makes it possible to optimize use of two flexible lines of different diameters.

Flexible lines of smaller diameter are easier to wind as superposed turns in carousel mode since it is more difficult to arrange touching turns of concentric increasing turn diameter on a plane in rotary basket mode with small-diameter lines.

Furthermore, flexible lines of relatively small diameter have a minimum radius of curvature that is also relatively small, thus enabling them to be wound on a central cylinder of relatively small diameter, thereby achieving a corresponding increase in the maximum storage capacity in carousel mode in terms of the length of flexible line that can be stored.

Also preferably, in said third embodiment of the storage and handling device of the invention, two flexible lines are wound on the mixed storage and handling device comprising:

-   -   a said first line, preferably a first flexible pipe, of smaller         diameter wound on a said central cylinder in carousel mode; and     -   a flexible second line, preferably a second flexible pipe, of         greater diameter wound in rotary basket mode around said inner         posts.

Advantageously, said turntable is made up of two concentric portions comprising:

-   -   an inner first turntable in the form of a disk suitable for         being driven in rotation; and     -   an outer second turntable of annular shape that is concentric         with said first turntable and arranged around said first         turntable, said second turntable being suitable for being held         stationary or for being driven in rotation together with said         first turntable when said first turntable is driven in rotation.

This embodiment is advantageous in that it serves to release an area of deck of varying size depending on the storage capacities in use of the storage device.

Thus, the inner first turntable may be used in carousel mode, in basket mode, and in mixed mode, in which case the outer second turntable either has no posts if the first turntable is used in carousel mode only, or else it has only said retaining posts if said first and second turntables are driven together in rotation as a unit and used in basket mode or in mixed mode, or else it has said retaining posts and said inner winding support posts if the first and second turntables are suitable for being driven together in rotation as a unit and used in basket mode or in mixed mode.

In a first preferred embodiment, the top face of said turntable is plane and substantially at the same level as the plane of said deck around said turntable.

In another embodiment, the top of said turntable is conical in shape, preferably centered on the middle longitudinal axis XX′ of the ship, presenting a half-angle at the apex α greater than 95 grad, preferably equal to 98 grad to 99 grad, more preferably a half-angle at the apex α of value substantially identical to the angle of inclination relative to the vertical of said two plane portions P₁, P₂ of the deck of the ship, respectively sloping at a small angle β relative to the horizontal to starboard P₂ and to port P₁ from a central ridge arranged said middle axial longitudinal direction XX′ of the ship.

It can be understood that when said turntable is a double turntable constituted by a said inner first turntable and a said annular second turntable, said first turntable is conical in shape and the second turntable is frustoconical in shape having the same half-angle at the apex.

Under all circumstances, each portion of said turntable, or where appropriate each portion of said second turntable does not project, in a direction perpendicular to said plane, beyond the level of said plane of the deck closest to which it is juxtaposed, i.e. the plane of said deck that is situated on the same side of said central ridge as said turntable portion.

The present invention also provides, more particularly, a ship for laying line at sea in accordance with the invention and further comprising a J-lay tower and at least one said flexible line wound around a said storage and handling device including a holder and guide device for holding and guiding a line portion extending between said holder and guide device and the wound line, said line including a curved second line portion of catenary shape that is subjected to the tension solely of its own weight extending between said holder and guide device and a sheave arranged at a greater height on the tower, preferably at the top of the tower, and a third line portion extending in rectilinear manner within the tower being tensioned with the help of a second traction device secured to said J-lay tower and preferably of the caterpuller type.

The means suitable for moving said first line portion vertically and/or horizontally and extending between said holder and guide device and the already-wound or still-wound line on said winding supports, depend on the embodiment of the storage and handling device, and they may comprise the following variants:

1) in a “rotary basket” type embodiment of the storage and handling device: a motor and guide rails and/or slideways suitable for moving said holder and guide device horizontally along said rail and/or slideway that is horizontal and supported by a horizontal cross-beam of a support gantry of said holder and guide device;

2) in a “carousel” type embodiment: a motor and vertical guide rails and/or slideways suitable for moving said traction device vertically along said rail and/or slideways supported by a post and/or a tower carrying said traction device;

3) in a “mixed” carousel and rotary basket embodiment: a motor suitable for vertically moving a said horizontal transverse beam supported by a tower or post of a gantry, and a motor suitable for horizontally moving said holder and guide device along said horizontal transverse beam; and

4) in all of the various “carousel”, “rotary basket”, and/or “mixed” embodiments, it is also possible to use auxiliary means such as hinged arms, suitable for moving said first line portion vertically and/or horizontally and co-operating with a holder and guide device that is stationary and/or that is itself suitable for being moved vertically and/or horizontally.

Still more particularly, said flexible line is an undersea flexible line.

The present invention also provides a method of laying a flexible line at sea from a ship of the invention, in which method the following steps are performed:

1) moving the ship in a manner that is synchronized with the running of the line through said second traction device within the J-lay tower, preferably a said second caterpuller; and

2) unwinding said line by actuating in synchronized manner rotation of said turntable, and moving said first line portion that extends between said holder and guide device and the wound line in such a manner as to maintain the curvature of said line portion extending between said holder and guide device and said sheave arranged at a greater height on the tower, with a catenary curve of curvature that is at all points greater than the minimum curvature that is acceptable for the flexible line, and preferably in such a manner that said catenary line portion does not touch the deck of the ship.

In a first implementation of the method of the invention, a said flexible line wound in carousel mode is unwound by exerting substantially constant tension on said first line portion extending substantially horizontally between the line holder and guide device and the line wound on a said central cylinder with the help of a traction device, preferably of the caterpuller type, and located at said line holder and guide device.

It can be understood that this first implementation of the method can be performed with a storage and handling device of the “carousel” type or of the “mixed” type.

In a second implementation of the method of the invention, a said flexible line wound in rotary basket mode is unwound without exerting tension on said first line portion extending in an inclined position between the line holder and guide device and the wound line, by synchronizing the travel speed of the line with the help of a traction device, preferably of the caterpuller type, and located at said line holder and guide device, with the speed of rotation of said turntable.

It can be understood that this second implementation of the method of the invention may be performed with a storage and handling device of the “rotary basket” type or of the “mixed” type, as described above.

In a preferred implementation of the method of the invention, a mixed type storage and handling device is used with:

-   -   a said first line, preferably a first flexible pipe, of smaller         diameter wound on a said central cylinder in carousel mode; and     -   a flexible second line, preferably a second flexible pipe of         larger diameter, wound in rotary basket mode on said inner posts         and retained by said peripheral retaining posts,

said method being characterized in that the following steps are performed in succession:

1) unwinding and laying said second line at sea; then

2) removing said inner posts and said peripheral retaining posts; and

3) unwinding and laying said first line at sea.

It is necessary to remove the specific accessories of said rotary basket in order to enable said first line portion to be moved in vertical translation for the purpose of spooling it while unwinding it.

Conversely, in a method of storing two flexible lines by winding them on a “mixed” type storage and handling device, the following successive steps should be performed:

1) winding said first line around said central cylinder in carousel mode;

2) mounting “rotary basket” type accessories comprising said inner and winding support posts and said peripheral retaining posts; and

3) winding said second line around said inner winding support posts of the rotary basket, in rotary basket mode.

BRIEF DESCRIPTION OF THE DRAWINGS

Other characteristics and advantages of the present invention appear better in the light of the following detailed description made in illustrative and non-limiting manner, and with reference to the drawings, in which:

FIG. 1 is a side view of a laying ship fitted with a J-lay tower and a storage and handling device for a flexible line wound in a mode referred to as “carousel” mode;

FIG. 1A is a side view of various accessories of said carousel for being secured in releasable manner, i.e. in separable manner, to a turntable of a FIG. 1 storage and handling device, the accessories being installed on the deck of the laying ship and on said turntable, which turntable is substantially in continuity with the plane of said deck;

FIG. 1B is a plan view of the turntable showing the means for attaching the various accessories;

FIG. 1C is a side view of the deck of a ship including a turntable of a storage and handling device of the invention, said turntable being substantially in the same plane as said deck;

FIG. 1D is a side view of said FIG. 1 carousel showing in detail the sequence for installing the various turns and layers of flexible line on the cylinder of said carousel, while winding at the stage of winding from the last turn but one at the top of the third layer;

FIG. 2 is a side view of a laying ship fitted with a J-lay tower and a storage and handling device for a flexible line wound in a mode referred to as “rotary basket” mode;

FIG. 2A is a plan view of the FIG. 2 rotary basket type storage device;

FIG. 2B is a side view shown partially in section on the right-hand side of a line AA of FIG. 2A, showing the sequence for placing the various turns and layers of flexible line on the turntable constituting the bottom of the rotary basket type device at the stage of winding the second concentric turn of the third layer superposed on top;

FIG. 2C is a plan view of the spooler device 2 of a FIG. 2 rotary basket type device, that is also capable of co-operating with a FIG. 1 carousel type device 3, or indeed with a mixed device as described below with reference to FIGS. 3C and 3D;

FIGS. 3A, 3B, and 3C are side views, partially in section on the right, showing details of a preferred version of the invention describing a mixed carousel and rotary basket storage and handling device in which a first flexible line 7-1 is stored in carousel mode, being wound around a central cylinder (FIGS. 3A, 3B, and 3C), and a second line 7-2 is stored in rotary basket mode against the periphery of said rotary basket, said second line being wound around first intermediate posts or inner posts 9 c forming second winding supports arranged around said first wound line (FIGS. 3B and 3C). In FIG. 3A, only the first line is shown being wound in carousel mode. In FIG. 3B, there are also shown the first intermediate posts 9 c serving as a second winding support for a second line in rotary basket mode while winding in rotary basket mode. Furthermore, in FIG. 3C, there is also shown the second line being wound in rotary basket mode on the accessories of the rotary basket, the peripheral posts 9 a serving as peripheral retaining posts for the second line;

FIG. 3D shows a mixed carousel and rotary basket type storage and handling device having wound thereon a first line 7 ₁ in carousel mode, a second line 7 ₂ in rotary basket mode, and a third line 7 ₃ in rotary basket mode;

FIG. 3E shows a central cylinder of a device of the invention fitted with a top plate 3 b at the top of the central cylinder and with an intermediate circular plate 3 b′ surrounding said central cylinder, thereby enabling two first lines 7-1 a and 7-1 b to be wound thereon;

FIG. 4 is a side view of a laying ship fitted with a J-lay tower and a prior art device for storing and handling a flexible line of the type having motor drive that is movable on rails and suitable for fitting successively to each of the drums installed in line one behind another on the deck of the ship;

FIG. 5 is a side view of a laying ship fitted with a J-lay tower, while in operation laying rigid pipes, by assembling prefabricated strings together within said J-lay tower, said strings being stored on the deck of the ship on the turntable of a device of the invention after its accessories have been removed;

FIG. 6A is a plan view of an installation ship fitted with a turntable centered on the middle longitudinal axis XX′ of the ship, the turntable having a diameter that is slightly less than the total width of said ship;

FIG. 6B is a plan view of an installation ship fitted with a double turntable installed offset to port relative to the middle longitudinal axis XX′ of the ship;

FIG. 7A shows a plane turntable seen in vertical section, the turntable being centered on the longitudinal axis XX′ of the ship as shown in FIG. 6A, the deck of the ship being constituted by two planes P₁ and P₂ sloping at respective angles β to port P₁ and to starboard P₂ on either side of a central ridge running along the longitudinal direction XX′ of the ship; and

FIG. 7B is a vertical section view of a turntable having a top face S that is conical in shape and centered on the longitudinal axis XX′ of the ship, with a half-angle at the apex α corresponding to the slope angle relative to the vertical of the two sloping planes respectively P₁ to port and P₂ to starboard, constituting the deck 1 a of the ship.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS

FIG. 1 is a side view of a laying ship 1 fitted with a J-lay tower 12 and a device for storing and handling a flexible line in a carousel type first embodiment 3. The device is constituted by a turntable 3 a driven to rotate about an axis Z₁Z₁′ perpendicular to said turntable by rotation means 3 a′ shown in FIG. 1C, and including motor drive 3 a′-1 for imparting rotary drive to gearing 3 a′-2 at the periphery of said turntable 3 a, said turntable 3 a being driven in rotation because it co-operates with a central rotary shaft 3 a′-5 on the same axis Z₁Z₁′ and co-operating with wheels 3 a′-3 situated under said turntable and over a floor 3 a′-4 fastened to the load-carrying structure of the hull and of the deck of the ship, or “hull girder”.

In a manner known to the person skilled in the art, the portion 1 c of the hull girder outside the cavity 1 b comprises under the deck, and as shown in FIG. 1C:

-   -   main transverse structural elements or main “frames” 1 d;     -   secondary transverse structural elements or “bulb profiles” 1 g;         and     -   longitudinal primary beams 1 f.

Creating a cavity 1 b is known to the person skilled in the art, in particular for creating a cavity that gives access from the deck to the holds of the ship.

In order to create the circular cavity 1 b, the portion 1 l of the hull girder is configured within the cavity 1 b with lower additional reinforcing elements 1 f, comprising:

-   -   main transverse reinforcing elements forming said frames 1 e and         secondary transverse reinforcing elements in the form of bulb         profiles 1 k under the floor 3 a-4 b that are closer to one         another in the longitudinal direction XX′ than are the frames 1         d and the bulb profiles 1 g in the portion 1 c of the hull         girder;     -   lower longitudinal beams 1 h also supporting said floor and the         rotation shaft 3 a′-5, that are closer to one another in the         transverse direction perpendicular to the longitudinal direction         XX′ than are the beams 1 l in the portion 1 c of the hull         girder;     -   the motor 3 a′-1 and gearing 3 a′-2 being fastened to structural         elements 1 c of the hull girder at the margin of the cavity         and/or to reinforcing elements 1 f within the cavity; and     -   the wheels 3 a′-3 being supported by said floor.

The wheels 3 a′-3 are interposed between the turntable 3 a and the floor 3 a′-4, preferably on a plurality of circles of decreasing diameter about the same vertical axis Z₁Z₁′ for the purpose of supporting the weight of the turntable, of the equipment, and of the flexible lines, and allowing the turntable 3 a to turn about the central axis of rotation 3 a′-5. For clarifying the drawings, the various figures show only one series of wheels 3 a′-3 distributed on a single circle of diameter substantially less than the outside diameter of said turntable. At the periphery of the cavity, the motor 3 a′-1 is fastened on a transverse frame 1 d or on a bulb profile 1 g supporting the deck and co-operates with a toothed system in gearing 3 a′-2 mounted on and/or co-operating with the periphery of said turntable 3 a in order to rotate it.

The turntable is then installed in said cavity above said wheels and floor. The floor 3 a′-4 performs the same role as the deck plate 1 a in terms of strength. The assembly is incorporated in the cavity 1 b in the deck of the ship, as shown in FIG. 1C in such a manner that the top plane of said turntable is substantially at the same level as the deck 1 a of said ship.

Thus, it is essentially the hull girder, i.e. the load-carrying structure of the hull of the ship that serves to transfer all of the vertical loads from the turntable and its load, and also serves to provide the rigidity needed for supporting the turntable and for loading it.

On its top face, said turntable has attachment elements 4 a, 4 a-4 b serving to secure a variety of accessories that are described in greater detail in the following description of the invention. Said attachment elements 4 are constituted, for example, by T-shaped grooves 4 a similar to those commonly used on machine tools, and as shown in plan view and in section view in FIG. 1B, or indeed mooring elements 4 b similar to those used for stowing containers on board trucks or container carrier ships, or finally, merely threaded holes drilled in the turntable for receiving stowage lugs. Thus, when no accessory is installed on said turntable, the deck of the ship is substantially plane and available for transporting loads or for performing a variety of operations, such as those shown in FIGS. 4 and 5, i.e. conventional laying of flexible lines of flexible pipe or electric cable type using winches 22 a-22 d with their axes of rotation parallel to the plane of the deck and perpendicular to the axis XX′ (FIG. 4A), or else laying rigid lines, e.g. by assembling successive strings together (FIG. 5), or indeed transporting and handling all types of large-capacity and large-dimension structures, without any need to disassemble the component elements of said turntable 3 a and of its supporting structure, as is needed in the prior art.

In the carousel mode of the storage and handling device 3, accessories are installed on the turntable 3 a as shown in FIG. 1A. These accessories comprise a first winding support element constituted by a cylinder 3 c that is of tapering cylindrical shape or preferably of right cylindrical shape of axis Z₁Z₁′ that preferably coincides with the axis of said turntable 3 a, together with a top plate 3 b that is preferably circular and that has the same vertical axis ZZ′. The top plate 3 b is secured to the top of the cylinder 3 c, with the base of the cylinder 3 c being secured to the turntable 3 a by the attachment elements 4. A line 7 is wound around the cylinder 3 c between the top plate 3 b and the turntable 3 a that constitutes a bottom plate. A first caterpuller 5 with tracks or tires and known to the person skilled in the art is arranged between the carousel type device 3 and the J-lay tower 12, and it serves in known manner to exert tension on the horizontal first portion 7 a of flexible line 7 that extends between the caterpuller 5 and the last turn of the last layer of the wound line. This tension is adjusted so that said tension is maintained at a substantially constant value, e.g. a tension of 5 t, so that the winding of said line on the carousel remains organized, as shown in FIG. 1D, i.e. so that the turns 7 i-1 to 7 i-l, with l=8, in each of the cylindrical layers 7 i with i=1 to 3 being concentric, and with each being made up of superposed helical turns that remain stable and ensuring that the set of turns does not collapse, which would lead to turns overlapping and/or would run the risk of severely damaging said flexible line. While loading/winding the line on the carousel or while unloading/unwinding the line, in order to ensure that the carousel type device 3 operates correctly, use is made of a spooler device 2 suitable for moving the caterpuller 5 vertically along a support element 6 extending in a direction Z₂Z′₂ perpendicular to said deck so that the first portion 7 a of the line that extends between the chain caterpuller 5 and the device 3 always remains substantially horizontal. Said support 6, installed to port, is constituted by a tower or post that is provided with elements for guiding the caterpuller 5 and a motor drive 2 a, the base of the post 6 being secured at 1 b′ to the deck 1 a of the ship close to the carousel 3, preferably as close as possible. Thus, while loading/winding the flexible line 7, 7-1 on said carousel 3, the turntable 3 a is rotated clockwise, and in conventional manner the vertical position of the first caterpuller 5 is adjusted so that the first portion 7 a of line between the caterpuller 5 and the carousel 3 remains substantially horizontal and the turns 7 ₁-1 to 7 ₁-9 of line wind properly one above another, while remaining in intimate contact with the preceding turns, as the first layer 7 ₁ closest to the central cylinder rises, and then so that the turns 7 ₂-9 to 7 ₂-1 of line wind one below another in juxtaposed manner against the central cylinder 3 c while building up the second layer 7 ₂ until reaching the turntable, and then causing the caterpuller 5 to rise once more in order to wind the third layer 7 ₃ of turns 7 ₃-1 to 7 ₃-9. Throughout the duration of loading, tension is kept substantially constant, e.g. at 5 t by means of the caterpuller 5, so that each of the turns is positioned against the preceding turn.

In FIG. 1D, the arrow shows the rising direction and then the falling direction and then once more the rising direction of the progression of layers 7 ₁, 7 ₂, and respectively 7 ₃, and the turns 7 i-1 to 7 i-n with i=1 to 3 and n=9 during the loading of the flexible line 7 by being wound onto the carousel 3.

More precisely, the first layer 7 ₁ is made starting from the bottom first turn 7 ₁-1 resting on the turntable 3 a up to the top last turn 7 ₁-9 beneath the top plate 3 b. Then, on reaching the top of the cylinder 3 c, winding begins with an additional layer 7 ₂ starting from a first top turn 7 ₂-9 under the top plate 3 b and arranged beside and against the last top turn 7 ₁-9 of the first layer 7 ₁, and then continuing down to the bottom last turn 7 ₂-1 of the second layer that rests on the turntable 3 a against and beside the bottom first turn 7 ₁-1 of the first layer 7 ₁. Then, a third layer 7 ₃ is built up starting with a first turn 7 ₃-1 placed against the turntable 7 ₂-1 resting on the turntable 3 a of the second layer 7 ₂ up to the top turn (not shown) of the third layer 7 ₃ under the top plate 3 b. As the first caterpuller 5 moves up and down, its speed of upward and downward movement is synchronized with the speed of rotation of the turntable. Throughout the entire period of unwinding or winding the flexible line 7 from or onto the carousel 3, said first caterpuller 5 is operated in a “constant tension” mode that is known to the person skilled in the art of winches. Thus, if the constant tension level is set for example at T₀=5 t, and if the tension tends to increase above the threshold set at T₀, the caterpuller unwinds a certain length of line, thereby having the effect of bringing the tension down to T₀; likewise, if the tension tends to drop below the threshold set at T₀, the caterpuller winds in a certain length of line, thus having the effect of returning the tension to T₀=5 t.

More particularly, the first caterpuller 5 co-operates with hydraulic actuator motors associated with a thermal unit and adjusted in such a manner that said first caterpuller 5 exerts a said traction T₀ on the line portion 7 a. Thus, if the turntable 3 a turns so as to unwind the flexible line 7, the tension in the line portion 7 a decreases so the caterpuller is automatically controlled to increase the tension that it exerts on the line portion 7 a by causing its tracks to turn, which tracks rub against the line in such a manner that the resulting tension exerted on the line portion 7 a by the first caterpuller is once more T₀. Conversely, while winding, if as a result of the turntable 3 a turning the tension in the line portion 7 a exceeds the tension T₀ in the line portion 7 a, the tracks of said first caterpuller 5 will turn in the opposite direction so as to move the line portion 7 a in the winding direction, i.e. towards the carousel 3 so as to bring the resulting tension in the line portion 7 a to the value T₀ and allow the flexible line to be wound on the carousel 3. Throughout transport, tension is also maintained in the line portion 7 a, e.g. in the range 2 t to 5 t, so as to avoid the tapering cylindrical assembly of line wound around the cylinder 3 c collapsing. If this tension were not exerted, the last turns might tend to move away from the cylinder, thereby causing the following turns to drop since they would no longer be held.

The line 7, in its line portion 7 b that extends from the caterpuller 5 to the top of the J-lay tower 12 adopts a catenary curve configuration. A sheave 8 of large size is installed on the hoisting ramp 2 a at the top of the tower 12, said flexible line portion 7 b entering at 8 a into the groove in said sheave 8 and the line portion 7 c leaving at 8 b, substantially on the laying axis of said tower 12. The flexible line then passes through at least one second caterpuller 12 b within the tower, which maintains the line portion 7 c in suspension at 7 c-1 down to the sea bottom. Thus, during laying, the flexible line 7 is under moderate tension in the portion 7 a, is substantially without tension other than that generated by its own weight in the line portion 7 b of catenary shape, and is then subjected to the laying tension generated by the second caterpuller 12 b in the portion 7 c by its own weight, said laying tension possibly being as much as 100 t to 150 t, or even more for lines of large diameter in great depths of water.

The travel of the line while it is being unwound from the carousel 3 and while it passes through the tower 12 is adjusted so that the curvature of the line portion 7 b remains between two limit curves 7 b-1 and 7 b-2 so as to maintain the curvature of said line portion 7 b with curvature that is always greater than the minimum curvature that is acceptable at its junction with the sheave 8 or at its junction with the caterpuller 5, i.e. curvature having a radius of curvature that is greater than the minimum acceptable radius of curvature for the line.

FIG. 2 is a side view of a laying ship 1 fitted with a J-lay tower 12 and with a second embodiment of a storage and handling device 9 that is of a type referred to as a “rotary basket” device. Said rotary basket is shown partially in section on the right, and is constituted by said turntable 3 a having a central cylinder 3 c placed thereon with a vertical axis Z₁Z₁′ that coincides with the axis of the turntable 3 a. A plurality of peripheral retaining posts 9 a are arranged at the periphery of the turntable, they extend vertically and they are preferably regularly distributed circularly about an axis Z₁Z₁′ that coincides with the axis of the turntable, said peripheral posts 9 a preferably being interconnected, e.g. at their tops, by a top rail 3 d of inside diameter that is preferably equal to or greater than the diameter of the circle that is tangential to the inside face of the set of posts 9 a. Thus, the top portion of the basket 9 is completely free, and it does not have a top plate at the top of the cylinder 3 c. Said flexible line 7 is handled with the help of a spooler device 2 that includes a said first caterpuller 5 mounted on a support gantry 6 at a fixed height relative to the deck 1 a of the ship and situated higher than the top rail 3 d so that the line portion 7 a going to the cylinder 3 c from the first caterpuller 5 slopes with a small amount of natural and non-stressed curvature. Said gantry 6 is shown in FIGS. 2A and 2C; it comprises a horizontal cross-beam 6 b extending in the transverse direction YY′ and fastened on two vertical side posts 6 a, such that first caterpuller 5 mounted on said cross-beam 6 b can move in the horizontal direction YY′ under motor drive (not shown), thereby constituting a device for performing horizontal spooling and suitable for directing the first flexible line portion 7 a towards the cylinder 3 c of the rotary basket in a direction that is kept permanently substantially tangential to the turn that is being formed, as shown in FIG. 2A.

In this second embodiment of the “rotary basket” type, as shown in FIGS. 2A and 2B, three superposed layers 7 ₁, 7 ₂, and 7 ₃ are thus formed, each comprising p=4 juxtaposed concentric turns 7 i-1 to 7 i-p with i=1 to 3, the turns being one against another. More precisely, the first layer starts from a first turn 7 ₁-1 resting on the turntable 3 a and arranged against the periphery of the central cylinder 3 c, and then by turning the turntable and moving the caterpuller 5 along the cross-beam 6 b, a second turn 7 ₁-2 is formed concentrically against the first turn 7 ₁-1, and so on, until a fourth concentric turn 7 ₁-4 reaches the periphery of the turntable 3 a on which it rests against the inside faces of a series of peripheral posts 9 a attached to the turntable 3 a and serving to retain the various superposed layers 7 ₁, 7 ₂, and 7 ₃. When the first layer has been completed, the line comes into abutment against the peripheral posts and can escape only by moving upwards, thereby naturally beginning the following layer. Thus, in order to make the second layer 7 ₂, the layer starts with a peripheral turn 7 ₂-4 arranged against the inside faces of the posts 9 a above the last turn 7 ₁-4 of the first layer, and then by moving the caterpuller 5 in the opposite direction horizontally along the cross-beam 6 b while continuing to turn the turntable 3 a, a concentric turn 7 ₂-3 is formed of slightly smaller diameter and is placed against the inside face of the flexible line constituting the turn 7 ₂-4, and so on so as to make the turn 7 ₂-2 and then 7 ₂-1 of decreasing diameters.

It can be understood that the retaining posts 9 a define the outermost position of the turns 7 i-4 and, during loading, they make it possible to begin the next layer up. These retaining posts 9 a also give the assembly a stable shape and in particular they ensure that the top layer is stable.

In this second embodiment of the storage and handling device 9 in rotary basket mode, the first caterpuller 5 serves only to hold the flexible line 7 so that the first and second line portions 7 a and 7 b adopt a certain amount of curvature without exerting significant tension in the first line portion 7 a between said first caterpuller 5 and the rotary basket device 9, in contrast to what happens with the carousel type first embodiment of the device 3.

In FIG. 2B, the direction in which loading is performed by winding layer after layer is shown in side view, showing how the turns progress and how the layers progress in this rotary basket type second embodiment of the storage and handling device 9, with each layer in this example having four turns. When the line 7 is taken to the rotary basket 9 for winding the line, or when the flexible line 7 is extracted from the rotary basket 9 for unwinding and laying at sea, the rotation of the turntable and the movement in translation of the spooler device in the horizontal direction are synchronized as is the speed of rotation of the tracks of the first caterpuller 5 in such a manner that the curvatures of the curves 7 a and 7 b remain acceptable, and in particular continue to have a radius of curvature that is greater than the minimum radius of curvature that is acceptable for the line.

As shown in FIG. 2A, during installation on site, the first caterpuller 5 is actuated to unwind and extract the flexible line 7 from the rotary basket type device 9 and direct it towards the sheave 8 on the tower 12, and then towards the second caterpuller 12 b. Thus, only the portion 7 c extending beneath the second caterpuller 12 b is subjected to a large amount of laying tension, and the other two line portions 7 a and 7 b are subjected only to low levels of handling tension, i.e. to tensions of a few tonnes, or even less.

FIG. 3C is a side view of a first variant of a mixed carousel and rotary basket embodiment of the storage and handling device 20 of the invention. In this variant embodiment, a tapering cylinder 3 c and a top plate 3 b of outside diameter smaller than the diameter of the turntable 3 a are installed initially, with said diameter of the top plate 3 b being greater than the diameter of the last layer 7 ₃ of the first line 7-1 in carousel mode as described above with reference to FIGS. 1 and 1A to 1D for storing in carousel mode. Thereafter, a first line 7-1 is stored by being wound on the device in carousel mode around a central cylinder 3 c arranged coaxially with said turntable 3 a, as shown in FIG. 3A. After the first flexible line 7-1 has been loaded/wound, the accessories are installed for transforming the device into rotary basket mode as follows. Installation comprises, in succession, installing a first series of posts in an intermediate position, referred to as “inner posts” 9 c that are preferably distributed uniformly and circularly and that are preferably secured via their bases to attachment elements on the turntable 3 a and via their tops to the top of the cylinder 3 c via the outside of the top plate 3 b. Said intermediate first set of posts can then act as the second winding support equivalent to the cylinder of the rotary basket type device 9 of FIG. 2 while winding a second line 7-2. Thereafter, a series of peripheral retaining posts 9 a is installed that are arranged in the manner described above at the periphery of the turntable 3 a, being secured via their bases to attachment elements 4 of the turntable 3 a and preferably being connected to one another at their tops by a circular rail 3 d. The second flexible line is then loaded/wound in rotary basket mode, as described above with reference to FIGS. 2 and 2A and 2C.

Said peripheral posts 9 a are preferably distributed regularly along the circular periphery of the turntable 3 a, and the inner posts 9 c are located close to the peripheral last layer 7 ₃ of the first line 7-1 wound on the cylinder 3 c.

Thereafter, a second flexible line 7-2 is stored by being wound in rotary basket mode. To do this, the first turn 7 ₁-1 of the first layer 7 ₁ of the second line 7-2 is wound against the outside face of the inner posts 9 c of the winding support for the second line 7-2, and then as described for the rotary basket mode, the second and third concentric turns 7 ₁-2 and 7 ₁-3 are wound that are juxtaposed side by side until reaching the inside faces of the peripheral posts 9 a, after which the second layer 7 ₂ is wound, being made up of turns 7 ₂-3, 7 ₂-2, and then 7 ₂-1 going respectively from the peripheral retaining posts 9 a towards the winding supports or inner posts 9 c, followed by the third layer 7 ₃ as described above going from the inner posts 9 c towards the retaining posts 9 a. To unwind the lines and lay them, it is appropriate to begin with unwinding and laying the second line 7-2 in rotary basket mode, after which the specific accessories should be removed from the rotary basket, i.e. the inner posts 9 c and the peripheral retaining posts 9 a, in order to unwind and lay the first line 7-1 in carousel mode.

This disassembly is necessary, since otherwise the first line portion 7 a leaving the device in carousel mode would not be able to extend horizontally while it is being spooled, since said intermediate posts 9 c and retaining posts 9 a would prevent it.

In FIG. 3D, there can be seen a second variant embodiment of a mixed carousel and rotary basket device 20 of the invention. A first flexible line 7-1 is stored initially in carousel mode on a central cylinder 3 c as described above. Thereafter, two respective series of first and second intermediate posts 9 c and 9 b are installed. The series of first intermediate posts 9 c is distributed on a circle of radius R1, the series of second intermediate posts 9 b being distributed on a second circle of radius R2 greater than R1. It is thus possible in rotary basket mode to load a second flexible line 7-2 against said first intermediate posts or inner posts 9 c out as far as said second intermediate posts 9 b acting as retaining posts for said second line 7-2. In FIG. 3D, the second line 7-2 is wound against the inner posts 9 c in five superposed layers, each comprising one helically arranged turn. The second intermediate posts 9 b serve as a third winding support for a third line 7-3, which is shown in FIG. 3D as having three layers 7 ₁ to 7 ₃, each of two juxtaposed concentric turns 7 _(i)-p with i=1 to 3 and p=1 or 2. The third line 7-3 is loaded by winding in rotary basket mode, but only after installing the peripheral retaining posts 9 a that serve to return the third flexible line 7-3.

While laying said line at sea, it is necessary to begin by unwinding and laying either of the second or third lines 7-2 or 7-3 in either order. It should be observed that if the second and third lines 7-2 and 7-3 were stored one after the other, i.e. one above the other in the same compartment between said inner posts 9 c and said peripheral retaining posts 9 a, then it would be necessary to unload and lay the line that was wound last, i.e. the top line. It would then not be possible to decide which line to lay, as is made possible by a mixed device having a plurality of series of intermediate posts as in the invention. In FIG. 3D, two series of intermediate posts 9 c and 9 b are used. Nevertheless, it is possible advantageously to use as many series of intermediate posts as needed as a function of the number of lines to be stored so as to retain the greatest possible flexibility for laying lines on site. In any event, it is appropriate to unwind and lay all of the lines that are stored in rotary basket mode before beginning to unwind and lay the first line that is wound in carousel mode, after removing the inner posts 9 c and the various intermediate and peripheral retaining posts 9 b and 9 a.

In FIG. 3E, there can be seen a variant embodiment in which the central cylinder is fitted with a top circular plate 3 b at its top and is surrounded by an intermediate circular plate 3 b′ having the same diameter and located halfway up, thus making it possible to wind a first line 7-1 a from the turntable 3 a up to immediately under the bottom face of the intermediate plate 3 b′, and then to wind a second first line 7-1 b from the intermediate plate 3 b′ up to and immediately under the face of the top plate 3 b. Under such circumstances, the two first lines 7-1 a and 7-1 b can be wound/unwound in either order.

FIG. 4 is a side view of conventional laying of flexible lines 7 in great depth from a series of horizontal-axis winches or drums 22 a-22 b-22 c-22 d having flexible line portions wound thereon. A drum drive unit 20 is suitable for sliding on rails 21 and for being fitted in succession to each of the drums 22 a-22 b-22 c-22 d in order to lift each one of them individually and in order to put them into rotation in succession so as to unwind the various flexible line portions 7 that have been wound onto the drums. Thus, when the first drum 22 a having a line wound thereon has been unwound, the end of said line 7 is made secure. Then the empty drum 22 a is put back on its support 22-1 and the drum motor drive 20 is moved to the following drum 22 b and the end of the line wound on the second drum 22 b is connected to the secured end of the flexible line that has already been laid. Thereafter, laying of flexible line continues by unwinding the various flexible line portions on the various following drums 22 c-22 d. This type of drum 22 a-22 b generally presents a diameter lying in the range 8 m to 12 m and a width lying in the range 5 m to 8 m, however it is capable of storing only a limited length of line portion, and the loaded drum may then weigh as much as 350 t to 750 t, or even more.

By comparison, storage in carousel mode as shown in FIG. 1 and FIGS. 3A-3D is advantageous when laying lines of very great length, since it makes it possible to store lines of greater length and/or of greater diameter, while avoiding the problems of connecting lines together as are encountered when line is stored as a plurality of segments on a plurality of drums. With flexible lines of large diameter, conventional storage on winches as shown in FIG. 4 is often not possible since the minimum radius of curvature of said flexible line is very large, typically up to 5 m or more, which would require drums 22 a-22 d of very large size that would then be unsuitable for handling. Storage in rotary basket mode as shown in FIGS. 2 and 3C-3D is much better adapted to lines of large diameter with a large minimum radius of curvature, since it enables long unit lengths thereof to be stored without running the risk of a radius of curvature that is less than the minimum radius of curvature. Mixed storage as described with reference to FIGS. 3A to 3C is preferred since that makes it possible to use carousel mode against the central cylinder 3 c to store a long length of first line 7-1 of small or medium diameter, and to store peripherally around said inner posts 9 c and second intermediate posts 9 b a second line 7-2 or indeed a third line 7-3 of long length and large diameter in rotary basket mode. The diameter of the circle along which the inner posts 9 c are placed to constitute the support element for winding the second line in rotary basket mode in the mixed device must be greater than the minimum diameter of curvature of said second flexible line 7-2, even though the central cylinder 3 c presents a diameter that is too small and thus incompatible with storing such a large diameter line 7-2. This winding technique of the rotary basket type is thus advantageous for flexible lines that are long and of large diameter and that cannot be wound on a cylinder of small diameter, given a minimum radius of curvature that is too great.

It is possible to wind lines of small or medium diameter, less than 200 mm over lengths of 1 km to 200 km on a cylinder 3 c having a diameter of 1 m to 15 m and a height of 3 m to 10 m, using a carousel type device of small or medium diameter. It is also possible with a rotary basket type device to wind lines of larger diameters, in particular diameters greater than 200 mm and for lengths that also exceed 1 km, with the circle of inner posts 9 c presenting a diameter greater 8 m, and in particular lying in the range 12 m to 30 m.

By way of example, a turntable 3 a having a diameter of 30 m and capable of supporting a load of 5000 t can be used to store a line over a height of 6 m as follows:

-   -   in carousel mode: 150 km of electric cable having a diameter of         150 mm and a weight per unit length of 25 kilograms per meter         (kg/m), i.e. about 76 layers of 40 turns representing a total         weight of about 4000 t;     -   in rotary basket mode: 12.5 m of flexible line having a diameter         of 500 mm, a weight per unit length of 350 kg/m and a minimum         radius of curvature R=5 m, giving about 12 layers of 18 turns,         representing a total weight of about 4500 t;     -   in mixed mode as shown in FIG. 3C:         -   in carousel mode: 10 km of umbilical 7-1 having a diameter             of 200 mm and a weight per unit length of 45 kg/m, i.e.             about 15 layers of 30 turns, representing a total weight of             about 450 t; plus         -   in rotary basket mode: 18.5 km of flexible line 7-2 having a             diameter of 400 mm, a weight per unit length of 200 kg/m and             a minimum radius of curvature R=6 m, i.e. about 15 layers of             20 turns, representing a total weight of about 3700 t,             together giving a total weight of about 4150 t; and     -   in the mixed mode of FIG. 3D:         -   in carousel mode: 22.5 km of umbilical 7-1 with a diameter             of 100 mm and a weight per unit length of 15 kg/m, i.e.             about 20 layers of 60 turns, representing a total weight of             about 350 t; plus         -   in rotary basket mode in a first circular corridor having a             cylinder diameter D1=10 m and a width of 1 m: 850 m of             flexible line having a diameter of 400 m, a weight per unit             length of 180 kg/m, and a minimum radius of curvature R=4 m,             i.e. about 13 layers of two turns, representing a total             weight of about 160 t; plus         -   in rotary basket mode in a second circular corridor having a             cylinder diameter D2=14 m and a width of 3 m: 3900 m of             flexible line having a diameter of 450 mm, a weight per unit             length of 300 kg/m, and a minimum radius of curvature R=4 m,             i.e. about 13 layers of six turns, representing a total             weight of about 1200 t; plus         -   in rotary basket mode in a third circular corridor having a             cylinder diameter D3=22 m and a width of 2.5 m: 3900 m of             flexible line having a diameter of 600 mm, with a linear             weight of 450 kg/m and a minimum radius of curvature R=6 m,             i.e. about ten layers of five turns representing a total             weight of about 1800 t, the entire weight then coming to             about 3510 t.

FIG. 6A shows a turntable 3 a with a diameter of 30 m and a capacity of 8000 t installed on the axis of the deck of an installation ship, near the bow.

FIG. 6B shows a double turntable 3 a with a diameter of 20 m and a capacity of 4500 t installed on the deck of an installation ship near the bow, said double turntable 3 a being offset to port so as to leave a free passage on the starboard side when said turntable is fitted in carousel mode, in rotary basket mode, or in mixed mode. The double turntable is constituted by an inner first turntable 3 a-a of diameter φ₁ that is in the shape of a disk, and an outer second turntable 3 a-b that is annular in shape and arranged concentrically around said first turntable, independently of said first turntable, with an outside diameter such that φ₂>φ₁. The two turntables lie in the same plane and substantially in the same plane as the deck of the ship. Motor drive acts on the inner turntable 3 a-a and the second turntable 3 a-b can either be held stationary while the first turntable is being driven in rotation, or else it can be secured thereto and driven in rotation together with said first turntable, or else it may be suitable for being driven in rotation independently of said first turntable, depending on the desired storage capacity. Thus, for storage of maximum capacity, the first and second turntables are secured to each other and a maximum storage capacity having a diameter φ₂ is available. If it is desired to use a smaller capacity, said second turntable is left stationary, being secured directly to the deck of the ship, and the first turntable is driven in rotation so as to make available only a smaller capacity corresponding to the diameter φ₁ of the first turntable 3 a-3. The advantage of this arrangement lies in the free passage on the deck of the ship beside the device which then corresponds to a wide corridor of width L₂ when it is desired to use only said first turntable 3 a-a, whereas the corridor is only of smaller width L₁ when the device is used to its maximum capacity, corresponding to the first and second turntables taken together. The wider corridor then enables additional equipment to be installed, and that constitutes a major advantage in numerous installation operations on oil fields at sea, because of the flexibility of the device.

For conventional line laying operations using 50 m long strings of rigid line 10 made up of unit lengths of line 11 stored on the deck of the ship and with a J-lay type tower 12, it is possible to remove said accessories 3 c-3 b, 9 a-9 b-9 c, and to leave the turntable 3 a in position, as shown in FIG. 5, since it is level with the deck and therefore does not interfere with the equipment that is put into place thereon.

The fact that the turntable 3 a is integrated in a cavity 1 b makes it possible to avoid a potential large loss of time should it be necessary to remove the turntable 3 a in order to release space on the deck 1 a.

Because the turntable is incorporated in the hull so as to be continuous with the plane of the deck, there is no need for it to be removed when it is desired to use the deck for other installations, thereby avoiding any need to take the boat out of operation for several days in port in order to perform this operation, and thus constituting a large economic advantage.

The deck 1 a of a ship generally presents two planes P₁ and P₂ that are at a gentle slope β relative to the horizontal, of less than 5%, and in particular in the range 1% to 2%, to port P₁ and to starboard P₂ running from a central axial ridge XX′ so that rain water or spray is directed to the sides of the ship for running off into the sea: such a deck therefore does not constitute a plane as such. Thus, said turntable is preferably plane and installed in such a manner that it does not project at any point beyond said deck of the ship, as shown in FIG. 7A. Thus, when it is not in use, there will exist a small offset in certain regions of the deck between said deck and said turntable, which offset can be compensated by wedges, e.g. wooden wedges, said wedges restoring surface continuity to the deck so as to enable the required equipment to be installed thereon. This local wedging is of thickness that varies depending on position and that lies in the range 20 mm to 200 mm-300 mm depending on the diameter of the turntable and the structure of the deck of the ship.

Nevertheless, it is advantageous to make a turntable that is not plane but that is slightly conical as shown in FIG. 7B with a half-angle α at the apex that coincides with the angle of inclination of the planes P₁ and P₂ of the deck of the ship to port and to starboard relative to a vertical axis perpendicular to said axial central ridge XX′, i.e. an angle α of more than 95 grad or an angle β of less than 5 grad, more particularly an angle β in the range 1 grad to 2 grad, i.e. a half-angle at the apex α of the cone of 98 grad to 99 grad. Such a conical turntable should then preferably be installed on the axis of the ship as shown in FIG. 6A and in FIG. 7B. In FIG. 7B, the conical turntable is arranged in such a manner that the portions of said turntable that are situated on either side of said central ridge XX′ do not project beyond the plane P₁ or P₂ of the deck situated on the same side of the central ridge XX′ in a direction that is perpendicular to said plane of the deck, and the apex of said turntable does not project vertically above the central ridge XX′ of said deck. In other words, said planes P₁ and P₂ on the port and starboard sides respectively of said deck are tangential to each of the portions of said turntable arranged on the same side, respectively as said port plane P₁ or said starboard plane P₂.

A turntable of the invention is typically made of steel presenting a diameter lying in the range 5 m to 50 m and a thickness lying in the range 100 mm to 800 mm.

A central cylinder 3 c may be made of machine-welded sheet metal presenting a height lying in the range 3 m to 10 m with a diameter of 1 m to 10 m in carousel mode and 5 m to 15 m in rotary basket mode.

The post or gantry 6 carrying the caterpuller and the spooler system should be positioned as close as possible to the outside of the top plate 3 b of the carousel and in practice within less than 5 m, and more preferably within less than 1 m.

The turntable 3 a should be positioned on the deck at a distance from the J-lay tower 12 that is sufficient to ensure that the radius of curvature of the line is greater than at least three times the minimum radius of curvature that the line can accept in the portion 7 b extending from said caterpuller to the top of the tower. Thus, the turntable 3 a should be arranged closer to the end of the ship that is remote from the tower than to the tower.

In an embodiment, the laying ship is not fitted with a laying tower, but with a chute, generally situated at the stern of the ship. This applies in particular for laying lines in shallow waters, in particular at depths of less than 500 m.

In an embodiment, in order to perform spooling so that the flexible line is always tangential on reaching the turn that is currently being wound or unwound, it is preferable to avoid moving the caterpuller and rather to make it co-operate with guide means such as a chute and a hinged arm suitable for moving laterally and thus in the transverse direction YY′ (rotary basket mode=horizontal spooling) of the ship or in the vertical direction ZZ′ (carousel mode=vertical spooling).

Constant tension devices, whether using tracks or tires, and spooling systems for winches and rotary baskets are known to the person skilled in the art, and in particular they are sold by the supplier Huisman (Netherlands). 

The invention claimed is:
 1. A laying ship for laying flexible undersea lines at sea, the ship having a hull with at least one girder and a deck including a cavity with a floor and having arranged therein a circular turntable and a motor-driven support and rotation device for said circular turntable, the carrier structure of said turntable having a floor incorporated in the hull girder and forming an integral portion of said hull girder, constituting a downward setback of a substantially circular portion of the deck, said turntable floor positioned within said cavity and constituting the top wall of the hull girder and performing a role that is similar to that of a deck plate in terms of the strength of said hull girder, said turntable floor being secured to additional reinforcing elements within the cavity that form integral portions of the hull girder such that the hull girder is capable of transferring a load constituted by at least said turntable and said support and rotary drive device, and is capable of providing stiffness required for supporting said load, the top face of said circular turntable not projecting beyond the level of the portion of the deck that is immediately juxtaposed laterally thereto, the periphery of said turntable coming level with said deck, said turntable being supported by and co-operating in rotation with elements of the support and rotation device within said cavity and fastened to the carrier structure of the hull of the ship, said rotary turntable presenting attachment elements on its top face and suitable for enabling flexible line winding supports of a flexible line storage and handling device to be reversibly attached thereto, said winding supports extending in a direction ZZ′ perpendicular to and above said plane of the deck of the ship, said attachment elements being distributed circularly and at different radial distances from the vertical central axis of rotation Z₁Z₁′ of said turntable.
 2. The laying ship according to claim 1, wherein said carrier structure of the hull includes additional reinforcing elements in said cavity, and said support and rotation device within said cavity comprises: a floor fastened to and supported by said additional reinforcing elements of said carrier structure of the hull under said floor; rotary guide elements supported by said floor and a rotary shaft supported by additional reinforcing elements of said carrier structure of the hull under said floor; and a motor and rotary drive elements for driving the turntable and said rotary shaft in rotation by actuating said motor, the elements being supported by said carrier structure of the hull within and at the periphery of said cavity.
 3. The laying ship according to claim 2, wherein said attachment elements comprise grooves and/or holes arranged radially and circularly over the surface of the turntable.
 4. The laying ship according to claim 1, wherein said laying ship supports a modular storage and handling device for storing flexible line by winding and unwinding the flexible line, the device comprising: a) said turntable supporting said accessories on its top face, which accessories are reversibly attached to said attachment elements, said accessories thus forming one or more winding supports extending in the perpendicular direction ZZ′ and above said plane of said deck of the ship, said winding supports being arranged circularly relative to the central axis of rotation Z₁Z₁′ of said turntable on the top face of said turntable; and b) a spooler device comprising a flexible line guide and holder device mounted on a second support element forming a post, a tower, or a gantry extending at least in a direction perpendicular to and above the deck of the ship in the proximity of said turntable and including motor-driven means for moving a first flexible line portion extending between said guide and holding device and said storage and handling device, and suitable for enabling vertical and horizontal movement of said flexible line portion relative to said second support element in order to enable said flexible line to be spooled around and against said winding supports.
 5. The laying ship according to claim 4, wherein the flexible line storage and handling device is of the type referred to as the “carousel” type and comprising: a) the winding support having a continuous wall in the form of a tapering or right central cylinder arranged coaxially about the axis of said turntable, said cylinder being surmounted by at least one top circular plate at its top; and b) the spooler device suitable for spooling said flexible line around and against said central cylinder in said “carousel” mode, comprising a line traction device suitable for tensioning said first line portion extending between said traction device and the already-wound or still-wound portion of line, and means suitable for moving said tensioned first flexible line portion vertically in such a manner as to keep it substantially horizontal while it is being wound or unwound so as to enable the line to be spooled in a plurality of coaxial layers of touching turns and enabling it to be unwound, said flexible line thus being wound or being suitable for being wound in “carousel” mode in a plurality of layers such that the turns of any one layer are helically superposed, the various layers forming juxtaposed coaxial cylindrical columns.
 6. The laying ship according to claim 4, wherein the flexible line storage and handling device is of the type known as the “rotary basket” type, comprising: a) said one or more winding supports comprise a plurality of winding supports in the form of inner posts arranged circularly relative to the axis of rotation Z₁Z₁′ of said turntable or a tapering or right central cylinder arranged on the axis with said turntable, and peripheral retaining elements extending in the perpendicular direction ZZ′ above said deck of the ship, being disposed circularly relative to the central axis of rotation Z₁Z₁′ of said turntable on the top face of said turntable; and b) said spooler device suitable for spooling said flexible line around and against said central cylinder or said plurality of inner posts in “rotary basket” mode comprising a line holder and guide device, and means suitable for moving the first flexible line portion in a transverse direction YY′ perpendicular to said vertical central axis of rotation Z₁Z₁′, the first flexible line portion extending in an inclined position between said holder and guide device and the already-wound or still-wound line, so as to enable the line to be spooled as a plurality of superposed layers of touching turns and so as to enable it to be unwound, the flexible line thus being wound or being suitable for being wound in “rotary basket” type mode as a plurality of superposed layers such that the turns in any one layer are juxtaposed concentrically, lying on a common plane and presenting diameters that increase from the first turn pressed against the winding support(s) out to the last turn coming into abutment against said peripheral posts, said line portion extending between the holder and guide device and the already-wound or still-wound line without being tensioned by said holder and guide device, which is held at constant height above the top ends of said winding supports and said retaining posts.
 7. The laying ship according to claim 4, wherein the flexible line storage and handling device is of the mixed carousel and the rotary basket type suitable for storing and handling at least two flexible lines and comprising: a first winding support for a first line, said first winding support having a continuous wall in the form of a tapering or right central cylinder arranged coaxially about the axis of said turntable; a plurality of second winding supports for winding a second line, the supports being in the form of inner posts arranged circularly relative to the central axis of rotation Z₁Z₁′ of said turntable at a constant radial distance from said central cylinder; peripheral retaining elements in the form of posts extending in the perpendicular direction ZZ′ above said plane of said ship deck, arranged circularly relative to the central axis of rotation Z₁Z₁′ of said turntable; said central cylinder being surmounted by a top circular plate at its top and of diameter such that said inner winding posts of the second line are secured to one another at their tops by being fastened to the periphery of said top plate, said first and second support elements and said retaining elements being arranged on the top face of said turntable; the spooler device including at least a second support element for supporting at least one flexible line guide and holder device suitable for enabling a said first flexible line portion to be moved vertically and horizontally, the first flexible line portion extending between the guide and holder device and the already-wound or still-wound line for spooling said flexible line around and against said winding supports, said second support element forming a tower or a gantry extending at least in a direction ZZ′ perpendicular to the plane of said and above said bridge, in the proximity of said turntable; said flexible line guide and holder device being suitable for enabling a first flexible line to be spooled around and against said central cylinder in “carousel” mode and comprising a line traction device suitable for tensioning the first line portion extending between the traction device and the already-wound or still-wound first line, said traction device being a caterpuller, and means suitable for vertically moving said first flexible line portion extending between the traction device and the already-wound or still-wound first line so that it can be tensioned and held substantially horizontally by said traction device to enable the first line to be spooled as a plurality of coaxial layers of superposed touching turns, said first flexible line thus being wound or being suitable for being wound as a plurality of coaxial layers such that the turns in any one layer are superposed helically, the various layers forming juxtaposed coaxial cylindrical columns such that two turns of two juxtaposed layers present different diameters; and said flexible line guide and holder device also being suitable for enabling a second flexible line to be spooled around and against said winding supports in the form of inner posts in “rotary basket” type mode, comprising a traction device for applying traction to the line, constituted by a caterpuller, and means suitable for moving said portion of the second flexible line in horizontal translation in a transverse direction YY′ perpendicular to said central axis of rotation Z₁Z₁′, said first portion of the second flexible line extending in an inclined position between the holder and guide device and the already-wound or still-wound second line in order to enable said second line to be spooled as a plurality of superposed layers of touching turns, said second flexible line thus being wound or being suitable for being wound as a plurality of superposed layers such that the turns in any one layer are concentrically juxtaposed, resting on a common plane and having diameters that increase from the first turn pressed against said winding supports in the form of inner posts to the last turn coming into abutment against said peripheral retaining posts, said first portion of the second line not being tensioned by said holder and guide device, which is held at a constant height above said winding supports and said retaining posts.
 8. The laying ship according to claim 7, wherein the laying ship has a single line guide and holder device suitable for being moved vertically or horizontally at constant height to move relative to a second support element of said flexible line guide and holder device, said second support element comprising a gantry.
 9. The laying ship according to claim 7, wherein two flexible lines are wound on a mixed storage and handling device comprising: a first line of smaller diameter wound on a said central cylinder in carousel mode; and a flexible second line of greater diameter than the diameter of said first line and wound in rotary basket mode around said inner posts.
 10. The laying ship according to claim 7, wherein said turntable is made up of two concentric portions comprising: an inner first turntable in the form of a disk suitable for being driven in rotation; and an outer second turntable of annular shape that is concentric with said first turntable and arranged around said first turntable, said second turntable being suitable for being held stationary or for being driven in rotation together with said first turntable when said first turntable is driven in rotation.
 11. The laying ship according claim 1, wherein the top face of said turntable is plane and substantially at the same level as the plane of said deck around said turntable.
 12. The laying ship according to claim 1, wherein the top face of said turntable is conical in shape, centered on the middle longitudinal axis XX′ of the ship, presenting a half-angle at the apex α greater than 95 grad, of half-angle at the apex α of value substantially identical to the angle of inclination relative to the vertical of said two plane portions P₁, P₂ of the deck of the ship, respectively sloping at a small angle β relative to the horizontal to starboard P₂ and to port P₁ from a central ridge arranged said middle axial longitudinal direction XX′ of the ship.
 13. The laying ship according to claim 1, wherein said ship further includes a J-lay tower and at least one said flexible line wound around a said storage and handling device including a holder and guide device for holding and guiding a line portion extending between said holder and guide device and the wound line, said line including a curved second line portion of catenary shape that is subjected to the tension solely of its own weight extending between said holder and guide device and a sheave arranged at a greater height on the tower, and a third line portion extending in rectilinear manner within the tower being tensioned with the help of a second traction device secured to said J-lay tower.
 14. The laying ship according to claim 1, wherein said flexible line is an undersea flexible line.
 15. A method of laying a flexible line at sea from a ship according to claim 13, the method wherein the following steps are performed: 1) moving the ship in a manner that is synchronized with the running of the line through said second traction device within the J-lay tower; and 2) unwinding said line by actuating in synchronized manner rotation of said turntable, and moving said first line portion that extends between said holder and guide device and the wound line in such a manner as to maintain the curvature of said line portion extending between said holder and guide device and said sheave arranged at a greater height on the tower, with a catenary curve of curvature that is at all points greater than the minimum curvature that is acceptable for the flexible line, and preferably in such a manner that said catenary line portion does not touch the deck of the ship.
 16. The method according to claim 15, wherein a said flexible line wound in carousel mode is unwound by exerting substantially constant tension on said first line portion extending substantially horizontally between the line holder and guide device and the line wound on a said central cylinder.
 17. The method according to claim 15, wherein a said flexible line wound in rotary basket mode is unwound without exerting tension on said first line portion extending in an inclined position between the line holder and guide device and the wound line, by synchronizing the travel speed of the line with the speed of rotation of said turntable.
 18. The method according to claim 15, wherein a storage and handling device of mixed type is used with: a first line of smaller diameter wound on a said central cylinder in carousel mode; and a flexible second line wound in rotary basket mode on said inner posts and retained by said peripheral retaining posts, said method wherein the following steps are performed in succession: 1) unwinding and laying said second line at sea; then 2) removing said inner posts and said peripheral retaining posts; and 3) unwinding and laying said first line at sea. 